SEISMIC RETROFIT OF INDUSTRIAL V BRACED STEEL STRUCTURES THROUGH ASYMMETRIC RE-CENTERING DISSIPATIVE DEVICES

Industrial steel structures designed following old technical standards often do not comply with the current anti-seismic requirements. Besides, their distribution of the masses and of the structural elements can be strongly different from building-like structures. Therefore, they can require retrofit interventions through tailored solutions. This is particularly relevant for structures with V shaped bracings and relevant masses concentrated in the higher floors, as the case of industrial buildings with internal storing silos. This situation indeed implies that the bracings are compressed by the self-weight of the silo's infill, and they can work in strongly asymmetric tension-compression way during the seismic event with several issues from the structural performance perspective. Also, in the case of performing seismic rehabilitation intervention through classical anti-seismic devices, there may be issues related with the accumulation of vertical displacements and dissipating energy in the bracings. To this end, a specific asymmetric re-centering dissipative device has been developed and experimentally tested. The paper presents the dynamic analyses carried out on a simple case-study structure aimed at assessing its seismic behavior in the cases in which Buckling Restrained Braces or Asymmetric Re-Centering Device are used as dissipative bracings.